After Sen. Russ Feingold (D-Wis.) was swept out and Gov. Scott Walker (R-Wis.) swept in during the 2010 Tea Party midterms, Republicans felt pretty good about their chances to flip another Senate seat when four-term Sen. Herb Kohl (D-Wis.) announced his 2012 retirement. Their odds got even better when they recruited longtime governor-turned-Bush administration official Tommy Thompson and he won the GOP nomination. Democrats chose liberal Rep. Tammy Baldwin, and as expected, Thompson led in the polls... until mid-September. Then, boosted by the Democratic National Convention and lopsided TV advertising, Baldwin opened up a sizable lead. Now, with both campaigns and their allies pouring money into the race, it's a dead heat.

KEY ISSUESThompson has been calling Baldwin too liberal for Wisconsin and Baldwin has accused Thompson of running through politics' revolving door from HHS secretary to high-paid Washington lobbyist. In terms of specific issues, Democrats have hit Thompson for telling a Tea Party group in June he'll "come up with programs to do away with Medicaid and Medicare" (he says he wants to "save" the programs, not end them), while Republicans attack Baldwin for being to the left of President Obama on health care by supporting a Medicare-for-all option for ObamaCare. With two weeks left in the race, Thompson unleashed a "brutal" ad attacking Baldwin for voting against a 2006 bill commemorating the fifth anniversary of the 9/11 terrorist attacks. Baldwin retaliated with her own ad accusing then-HHS Secretary Thompson of neglecting the health needs of firemen, cops, and others who responded to the 9/11 attacks in New York City, then getting an $11 million HHS contract to care for those same first responders after he left office. (The details on both ads are here.) There's one issue that, perhaps surprisingly, hasn't been part of the race: Baldwin's sexual orientation, says David Weigel at Slate. "Scott Walker's state may elect the first openly gay senator in American history, and it's a total nonissue."

Three election forecasters — Charlie Cook, Stu Rothenberg, and Larry Sabato — rate the race a toss-up, while New York Times politics number-cruncher Nate Silver scores it "likely Democratic." Given her liberal voting record, Baldwin "is expected to underperform Obama in Wisconsin," says Huffington Post Pollster. That "would make the math very difficult for her if Mitt Romney carries or comes close to winning the state."

CASH ON HAND (as of Sept. 30):Thompson: $2 million on hand; $5.7 million totalBaldwin: $3.5 on hand; $11.2 million total